A viral challenge circulating on the social media app TikTok has Massachusetts firefighters issuing an alert. It’s called the “outlet challenge,” and it involves partially inserting the plug of a cellphone charger into an outlet, then sliding a penny down the wall onto the exposed prongs.

A viral challenge circulating on the social media app TikTok has Massachusetts firefighters issuing an alert. It’s called the “outlet challenge,” and it involves partially inserting the plug of a cellphone charger into an outlet, then sliding a penny down the wall onto the exposed prongs.